The present invention relates to a material that is capable of forming a pattern of the order of nanometers in a self-organized manner on a substrate, the pattern being utilized as a mask for forming a nanopattern excellent in regularity. The present invention also relates to a material that is capable of forming a bulk structure of the order of nanometers in a self-organized manner, the structure being utilized as it is as a nanostructure of high regularity, or utilized as a template for forming another nanostructure of high regularity. The material of the present invention is applied for manufacturing a magnetic recording medium for hard disks having a recording density of 10 Gbit/inch2 or more, an electrochemical cell, a solar cell, a photovoltaic device, a light emitting device, a display, a light modulating device, an organic FET device, a capacitor, a high-precision filter, etc.
Needs for a fine pattern or structure are increasingly desired, as improvement in performance of electronic parts. In the electronic parts such as LSI and liquid crystal display, for example, micro-fabrication techniques are required. Many devices such as an electric cell and a capacitor are required small volume and large surface area. In future, a high-density three-dimensional packaging will be needed. Lithography is employed in these processes, and thus the manufacturing cost becomes higher as more micro-fabrications are needed.
On the other hand, there is a technical field where precision as high as in the case of the lithography is not needed, although a patterning of the order of nanometers is required. However, a simple patterning method has not known hitherto, there is no other choice to form a fine pattern by lithography using an electronic beam or deep ultraviolet ray in such a technical field. As mentioned above, in the lithography technique, operations are complicated and enormous investment is required as the processing dimension becomes smaller.
Under these circumstances, as a simple pattern forming method alternative to the lithography technique, a method utilizing a structure having micro polymer phases formed in a self-developed manner from a block copolymer.
For example, P. Mansky et al. have reported, in Appl. Phys. Lett., Vol. 68, No. 18, p. 2586–2588, a method in that a sea-island type microphase-separated film made of a block copolymer of polystyrene and polyisoprene is formed on a substrate, the polyisoprene is decomposed by ozonation and removed to form a porous film, and the substrate is etched using the porous film as a mask, thereby forming a pattern, to which the structure having micro polymer phases is transferred, on the substrate. In addition, M. Park et al. have reported, in Science, Vol. 276, 1401–1406, a method in that a sea-island type microphase-separated film made of a block copolymer of polystyrene and polyisoprene is formed on a substrate, the polyisoprene phase is doped with osmium oxide by a vapor phase reaction to improve etch resistance, and a pattern is formed using the polyisoprene phase selectively doped with osmium oxide as a mask.
Such a method using the microphase separation of the block copolymer is simple and inexpensive as compared with the lithography technique. However, the ozonation is complicated as well as needs relatively long reaction time, so that it is difficult to improve throughput. Also, since the osmium oxide has high level of toxicity, it is scarcely used in general purpose from the viewpoint of safety.